The temperature dependence of the dip is shown in Fig. REF . The half width
of the dip at \(T=0.4\)  K, taken at the average between the minimum \(dI/dV\)  and
the relative maximum near \(eV=0.001\)  is 3.1 K,
near the reported one [1]} 2.7 K. With
increasing temperature, the low-energy dip in the spectral density decreases
and eventually disappears, as expected. The effect is much more pronounced
at low temperatures. The same trend is observed in the
experiment [2]}. The inset shows the results in a scale of energies
similar to that of the experiment (Fig. 2 of Ref. yang).
